From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 3 Mar 2003 04:37:48 +0000 (+0000)
Subject: Prevent clustering on incomplete indexes: partial indexes are verboten,
X-Git-Tag: REL7_3_3~70
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6b305090ed2f307c9189fe938aa0054add6ef872;p=thirdparty%2Fpostgresql.git

Prevent clustering on incomplete indexes: partial indexes are verboten,
as are non-amindexnulls AMs unless first column is attnotnull.
---

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index fa414320a31..313b0eff137 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.91 2002/11/02 21:20:40 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.91.2.1 2003/03/03 04:37:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -110,6 +110,34 @@ cluster(RangeVar *oldrelation, char *oldindexname)
 			 RelationGetRelationName(OldIndex),
 			 RelationGetRelationName(OldHeap));
 
+	/*
+	 * Disallow clustering on incomplete indexes (those that might not index
+	 * every row of the relation).  We could relax this by making a separate
+	 * seqscan pass over the table to copy the missing rows, but that seems
+	 * expensive and tedious.
+	 */
+	if (VARSIZE(&OldIndex->rd_index->indpred) > VARHDRSZ) /* partial? */
+		elog(ERROR, "CLUSTER: cannot cluster on partial index");
+	if (!OldIndex->rd_am->amindexnulls)
+	{
+		AttrNumber	colno;
+
+		/*
+		 * If the AM doesn't index nulls, then it's a partial index unless
+		 * we can prove all the rows are non-null.  Note we only need look
+		 * at the first column; multicolumn-capable AMs are *required* to
+		 * index nulls in columns after the first.
+		 */
+		if (OidIsValid(OldIndex->rd_index->indproc))
+			elog(ERROR, "CLUSTER: cannot cluster on functional index when index access method does not handle nulls");
+		colno = OldIndex->rd_index->indkey[0];
+		if (colno > 0)			/* system columns are non-null */
+			if (!OldHeap->rd_att->attrs[colno - 1]->attnotnull)
+				elog(ERROR, "CLUSTER: cannot cluster when index access method does not handle nulls"
+					 "\n\tYou may be able to work around this by marking column \"%s\" NOT NULL",
+					 NameStr(OldHeap->rd_att->attrs[colno - 1]->attname));
+	}
+
 	/*
 	 * Disallow clustering system relations.  This will definitely NOT
 	 * work for shared relations (we have no way to update pg_class rows